dissenting.
This Court has long recognized that great deference should be given to the interpretation of a statute by the administrative agency charged with enforcing and administrating the statute and that where the provisions of a statute are ambiguous or doubtful, the administrative agency’s “contemporaneous practical construction . will not be disturbed except for weighty reasons. [Cits.]” State of Ga. v. Camp, 189 Ga. 209, 210 (1) (6 SE2d 299) (1939). See also Kelly v. Lloyd’s of London, 255 Ga. 291, 293 (336 SE2d 772) (1985). This rule is applicable to the Public Service Commission’s interpretation of provisions in the Georgia Territorial Electric Service Act. E.g., City of LaGrange v. Ga. Power Co., 185 Ga. App. 60, 63 (363 SE2d 286) (1987), holding that
the PSC, as the agency charged with . . . the enforcement and administration of the Georgia Territorial Electric Service Act, is entitled to great deference in its interpretation of the Act. The administrative interpretation of a statute by an administrative agency which has the duty of enforcing or administering it is to be given great weight.
(Citations and punctuation omitted.) See also Colquitt EMC v. City of Moultrie, 197 Ga. App. 794, 796 (399 SE2d 497) (1990); North Ga. EMC v. City of Calhoun, 195 Ga. App. 382, 384 (393 SE2d 510) 1(1990). Because the majority fails to give any deference to the PSC’s [interpretation of the ambiguous language in the large-load exception [provision of the GTESA and provides no “weighty reason” for substituting its opinion for the reasoned expertise of the PSC, I must [respectfully dissent.
The issue in this case turns on the definition to be given the term |“one consumer,” as used in the large-load customer choice exception [set forth in OCGA § 46-3-8 (a) of the Georgia Territorial Electric Service Act. The PSC, in the exercise of its regulatory duties, addressed *708the question whether “one consumer” means the ultimate end user of the electricity or the entity with the direct contractual relationship with the electric supplier. After reviewing the evidence adduced before the hearing officer and entertaining oral argument in the course of a full commission review of this issue, the PSC held that because the GTESA is intended to regulate the provision of electric service by the many electric power suppliers within the State, OCGA § 46-3-2, the definition which best comports with the Act as a whole is that “one consumer” means the entity which has the direct relationship with the electric supplier. The record further reflects that the PSC took uniformity of application of the GTESA into consideration in ruling on the issue, after noting that residential customers are the only customer clients in this State who have not had the opportunity to benefit from the lower cost of large-load rates and that the Act expressly prohibits discrimination between classes of consumers, OCGA § 46-3-11 (a), thereby prohibiting any distinctions between the treatment of residential and commercial customers.
The majority refuses to accord any deference to the PSC’s expertise in the construction of this term, justifying its decision on the basis that “one consumer” is “plain and unambiguous,” despite the testimony presented before the PSC hearing officer, the arguments adduced on the issue, and the diametrically opposite opinions rendered by the PSC and the Court of Appeals on one hand and the superior court and the majority on the other. Given the complex regulatory world of the GTESA, I cannot agree with the majority that no ambiguities exist in defining “one electric consumer.” The majority’s own construction demonstrates the term’s ambiguity. The majority concludes that “one consumer” means the “user of the final product,” but at what point is usage determined? The majority notes that Dominion’s tenants were separately billed and their apartments sub-metered, but what if Dominion had chosen to provide electricity at a flat rate directly to the individual apartments? The tenants would still be the ones using the electricity, so would they not still be the “users of the final product”? What if the end user is not a tenant but a customer at a laundromat or a video game player at a pinball arcade? The ambiguity in “one consumer” is created by the number of choices available when determining where, along the continuum of usage,! the consumption of electricity occurs. I
The PSC considered the ambiguities in “one consumer” and con-j strued the term to mean that the “user of the final product” is the! user with the final direct contractual relationship with the electric* power server. The PSC’s clean, bright-line definition is entitled to! this Court’s deference and furthermore represents a sensible and! practical interpretation of this difficult term. The majority’s interpre-j tation totally ignores the contractual relationship an electric service! *709provider has with its customer, although that is the relationship which is regulated by the GTESA, and focuses on the unregulated relationship the customer may choose to enter into with third parties. By expanding the definition of “one consumer,” the majority has in effect improperly imposed a judicially-created on-going obligation on electric service providers to ascertain what their customers are doing with the electric services provided.2
The PSC construed “one consumer” in light of its expert knowledge of the manner in which electric service providers contract with customers, the customary usage with meter configurations, and the practical consequences of its interpretation. Thus, the PSC’s interpretation, unlike the majority’s, inflicts no adverse consequences upon the common use of master meter configurations in commercial settings3 and serves the non-discrimination policy of the GTESA by allowing multi-family residential customers to take advantage of the lower rates available under the large-load exception. The PSC has acted in a manner which best promotes the GTESA’s legislative goal of “assurfing] the most efficient, economical, and orderly rendering of retail electric service within the state.” OCGA § 46-3-2.
Our case law requires that we have “weighty reasons” before we disturb an administrative agency’s practical construction of ambiguous language in a statute it enforces. State of Ga. v. Camp, supra, 189 Ga. at 210 (1). The majority can produce no “weighty reasons” for a construction of OCGA § 46-3-8 (a) which ignores the functional application of the large-load exception, gives no deference to the expertise the PSC has gained by virtue of its regulatory and administrative duties over the electric power industry, promotes adverse consequences and undermines the legislative goals of the GTESA as set forth in OCGA § 46-3-2.4 Accordingly, because there are no reasons, *710weighty or otherwise, to justify this Court’s refusal to accord deference to the PSC’s ruling, I dissent to the reversal of the well-reasoned opinion by the Court of Appeals upholding the PSC and applying the correct interpretation of OCGA § 46-3-8 (a).
Decided March 19, 2001 Reconsideration denied April 12, 2001. Sutherland, Asbill & Brennan, James A. Orr, Charles B. Jones III, for appellant. Troutman Sanders, Kevin C. Greene, Helen O’Leary, James S. Hurt, Thurbert E. Baker, Attorney General, Robert S. Bomar, Deputy Attorney General, Harold D. Melton, Senior Assistant Attorney General, Daniel S. Walsh, Assistant Attorney General, for appellees. Alston & Bird, L. Clifford Adams, Jr., Peter M. Degnan, Robert J. Middleton, Jr., Tisinger, Tisinger, Vance & Greer, Richard G. Tisinger, Sr., Steven T. Minor, amici curiae.I am authorized to state that Justice Carley and Justice Hines join in this dissent.
Thus, an electric service provider would be required to ferret out changes in its customers’ operations so as to determine, for example, whether a grocery store customer, which decided to allow a bank branch or a fast food outlet to operate under its single meter, has invalidated the large-load exception under which electric service is provided to the store.
Expert testimony was adduced that military bases such as Fort Benning, shopping malls like Perimeter Mall, and commercial enterprises like the Galleria complex have a master meter configuration, whereby electricity is received at a master meter with sub-meters for individual stores or offices within the building or complex. A Georgia Power Company account executive for multi-family markets noted that there are other electric companies providing service to master-meter configured complexes within Georgia Power’s territory under the large-load exception.
In addition to generic dictionary definitions, the majority cites as support of its holding the “consistent” one-judge opinion rendered in City of Norcross v. Ga. Power Co., 197 Ga. App. 891 (399 SE2d 725) (1990). That case, however, is not only distinguishable on its facts (given the absence of any evidence that Dominion’s tenants possess any purchase options in the apartments they rent), but contains the express recognition that the “one consumer” requirement “could well apply” in factual situations involving a “multi-tenant office building that is conceived, used and will continue to be used as a unified rental premises, owned and *710operated by one entity.” Id. at 894 (2). Since this case before us now involves multi-tenant residential buildings that were conceived, are used and will continue to be used as a unified rental premises, owned and operated by one entity, the majority’s result hardly qualifies as “consistent” with the City ofNorcross opinion.